JP2011021701A - Self-tapping screw - Google Patents

Self-tapping screw Download PDF

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JP2011021701A
JP2011021701A JP2009167953A JP2009167953A JP2011021701A JP 2011021701 A JP2011021701 A JP 2011021701A JP 2009167953 A JP2009167953 A JP 2009167953A JP 2009167953 A JP2009167953 A JP 2009167953A JP 2011021701 A JP2011021701 A JP 2011021701A
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Prior art keywords
screw
thread
male
low
self
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JP4954248B2 (en
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Yukihiko Sugawara
幸彦 菅原
Shoichi Hayashi
正一 林
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Natec Co Inc
Tokyo Byokane Co Ltd
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Natec Co Inc
Tokyo Byokane Co Ltd
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Priority to JP2009167953A priority Critical patent/JP4954248B2/en
Priority to US12/831,365 priority patent/US8371787B2/en
Priority to CN201010232897.2A priority patent/CN101956749B/en
Publication of JP2011021701A publication Critical patent/JP2011021701A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
    • F16B25/001—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed
    • F16B25/0031—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed the screw being designed to be screwed into different materials, e.g. a layered structure or through metallic and wooden parts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
    • F16B25/0036—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw
    • F16B25/0042—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw
    • F16B25/0047—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by geometric details of the screw characterised by the geometry of the thread, the thread being a ridge wrapped around the shaft of the screw the ridge being characterised by its cross-section in the plane of the shaft axis

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Connection Of Plates (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-tapping screw capable of obtaining a large fastening force by carving high-accuracy female threads with small driving torque. <P>SOLUTION: The self-tapping screw has a screw shank 2 stretching down from a screw head, where the shank 2 portion stretching just under the screw head is furnished with a plurality of equally high male threads 3, and in continuity from the male threads 3, the forefront portion of the shank 2 is furnished with a plurality of low male threads 4 whose heights decrease gradually toward the end face of the forefront portion, and minute arcuate surfaces 7 are continuously formed in the joints between the upper and lower flanks 5 of each low male thread 4 and the upper and lower bottom surfaces 6, wherein each minute arcuate surface 7 is arranged extending over the joint of at least the lower flank 5 and the lower bottom surface 6 of each end-part equally high male thread 3a continuous to the low male thread 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、相手部材に穿設された下穴に雌ねじを刻設しながら締結を行うセルフタッピングねじに関するものである。   The present invention relates to a self-tapping screw that performs fastening while engraving a female screw in a pilot hole drilled in a mating member.

現在、市場に普及している電子機器、通信機器、事務機器等において、合成樹脂や金属などから成る相手部材に部品等の取付部材を取り付けるために、相手部材に予め雌ねじを刻設する工程を省略できるセルフタッピングねじが多用されている。   In order to attach a mounting member such as a component to a mating member made of synthetic resin or metal in electronic equipment, communication equipment, office equipment, etc. that are currently popular in the market, a process of engraving a female screw in advance on the mating member Self-tapping screws that can be omitted are frequently used.

そして、セルフタッピングねじにおいては、取付部材と相手部材とを締結する際に、できるだけ小さいねじ込みトルクで、精度の高い雌ねじを刻設して、大きな締結力が得られるようにすることが共通の課題となっている。   In the self-tapping screw, when fastening the mounting member and the mating member, it is a common problem to obtain a large fastening force by engraving a highly accurate female screw with as little screwing torque as possible. It has become.

特許文献１に記載のセルフタッピングねじ、特にねじ軸周面（谷底面）と下穴内周面との間にクリアランスを形成することを条件としない請求項１に記載の発明においては、ねじ軸先端からねじ頭直下に亘る全雄ねじ山において、鋭角度の断面三角形状の山頂部と、該山頂部の下部には前記山頂部よりも大きな角度にて谷底面に連なる裾広がりの左右の誘導脚辺部（傾斜平面）を有するねじ山拡大本体部とから成る二段形状の雄ねじ山を形成したセルフタッピングねじを開示している。   The self-tapping screw disclosed in Patent Document 1, particularly the screw shaft tip, which is not required to form a clearance between the screw shaft peripheral surface (valley bottom surface) and the pilot hole inner peripheral surface. In the all male screw thread extending from right to under the screw head, the top part of the triangular section with an acute angle, and the left and right guide legs with hems extending to the bottom of the valley at a larger angle than the summit part at the lower part of the summit part A self-tapping screw having a two-stage male screw thread formed of a thread enlarged body part having a portion (inclined plane) is disclosed.

実用新案登録第３１４００７４号公報Utility Model Registration No. 3140074

しかしながら、上記二段形状の雄ねじ山を有するセルフタッピングねじは、下穴内にねじ込む場合における初期ねじ込みトルク、即ち最初の二段形状雄ねじ山が下穴内周面に二段形状の雌ねじ溝を刻設する際のトルクが高くなる問題を有している。   However, the self-tapping screw having the two-stage male screw thread has an initial screwing torque when screwed into the pilot hole, that is, the first two-stage male screw thread has a two-stage female screw groove formed on the inner peripheral surface of the pilot hole. There is a problem that the torque at the time becomes high.

また、上記構成のセルフタッピングねじにあっては、雄ねじ山の山頂部の各フランク面とねじ山拡大本体部の各誘導脚辺部への転造時における材料の流れがスムーズとならず、谷底面や雄ねじ山の山頂部の各フランク面と拡大本体部の各誘導脚辺部に肌荒れやささくれ、または雄ねじ山山頂部に割れが生ずる問題を有している。 Further, in the self-tapping screw having the above-described configuration, the material flow is not smooth during rolling to the respective flank surfaces of the crests of the male screw threads and the respective guide leg sides of the thread expansion main body part. There is a problem that the surface of the flank and the flank surface of the top of the male screw thread and the induction leg side of the enlarged main body part are roughened and crushed, or the male screw thread peak is cracked.

本発明は、斯かる従来のセルフタッピングねじが抱える課題を有効に解決することができるセルフタッピングねじを提供するものである。
要述すると、本発明に係るセルフタッピングねじは、ねじ頭直下に延びるねじ軸部分にねじ山の高さが互いに等高の複数の等高雄ねじ山を形成すると共に、同ねじ軸の先端軸部にねじ山の高さが該先端軸部端面に向かって漸減する複数の低背雄ねじ山を上記等高雄ねじ山と連続して形成し、該低背雄ねじ山の上下フランク面と上下谷底面との各連設部に微小円弧面をそれぞれ連続して形成すると共に、該微小円弧面を上記低背雄ねじ山に連続する端部等高雄ねじ山の少なくとも下フランク面と下谷底面との連設部に亘って延在するように形成した。 The present invention provides a self-tapping screw that can effectively solve the problems of the conventional self-tapping screw.
In short, the self-tapping screw according to the present invention forms a plurality of contour male threads with the same thread height on the screw shaft portion extending directly below the screw head, and the tip shaft portion of the screw shaft. A plurality of low-profile male threads that continuously reduce the height of the thread toward the end face of the tip shaft, and are formed continuously with the contour male threads, and the upper and lower flanks of the low-profile male threads and the bottom of the upper and lower valleys A micro arc surface is continuously formed in each continuous portion, and the micro arc surface is connected to at least the lower flank surface and the bottom valley bottom surface of the high-altitude male screw thread that is continuous with the low profile male screw thread. It formed so that it might extend over.

好ましくは、上記低背雄ねじ山及び端部等高雄ねじ山の微小円弧面の曲率半径を０．２ミリメートルから０．６ミリメートルに設定する。
また、上記構成を採りながら、上記低背雄ねじ山と連続する等高雄ねじ山の断面形状を左右対称形状にし且つその山角度を４８度から５２度の範囲に設定する。
また、上記ねじ軸が全長において等径の円柱軸であり、該等径の先端軸部に上記低背雄ねじ山を形成する。 Preferably, the curvature radius of the micro arc surface of the low-profile male thread and the high-end male thread is set to 0.2 mm to 0.6 mm.
In addition, while adopting the above configuration, the cross-sectional shape of the iso-high male thread continuous with the low-profile male thread is made symmetrical, and the angle of the thread is set in the range of 48 to 52 degrees.
Further, the screw shaft is a cylindrical shaft having an equal diameter in the entire length, and the low-profile male screw thread is formed on the tip shaft portion having the same diameter.

依って、本発明に依れば、高さが漸減する低背雄ねじ山の形成と、該低背雄ねじ山及び端部等高雄ねじ山に形成した微小円弧面との相乗により、ねじ込み初期における相手部材へのストレスが緩和され、スムーズに雌ねじ溝を形成でき、初期ねじ込みトルクの軽減に寄与することができる。   Therefore, according to the present invention, by the synergy of the formation of the low-profile male screw thread whose height gradually decreases and the micro-arc surface formed in the low-profile male screw thread and the high-grade male thread such as the end part, The stress on the member is relieved, the female screw groove can be formed smoothly, and the initial screwing torque can be reduced.

また、低背雄ねじ山と端部等高雄ねじ山の微小円弧面で成形された微小凸曲面部により、後続する等高雄ねじ山のフランク面と谷底面との角隅部への材料移動がスムーズになされ、精度の高い雌ねじ溝を形成することができる。依って、等高雄ねじ山と雌ねじ溝との確実な係合が得られ、大きな締結力を得ることができる。   In addition, the small convex curved surface formed by the small circular surface of the low-profile male thread and the end of the high-grade male thread enables smooth movement of the material to the corners of the flank surface and valley bottom of the subsequent contour male thread. Thus, a highly accurate female thread groove can be formed. Therefore, reliable engagement between the contour male thread and the female thread groove is obtained, and a large fastening force can be obtained.

また、破壊トルク、即ち雌ねじが破壊するときのトルクを大きく、初期ねじ込みトルクを小さくすることができるので、ねじ込みトルク間隔を広く取ることができるため、合成樹脂や金属からなる相手部材に対する共通トルク帯域を充分に確保でき、何れの材料に対しても、安定してねじ込み作業を行うことができる。   Moreover, since the breaking torque, that is, the torque when the female screw breaks can be increased and the initial screwing torque can be reduced, the screwing torque interval can be widened, so that a common torque band for the mating member made of synthetic resin or metal Can be secured sufficiently, and any material can be screwed in stably.

更に、本発明によれば、従来の二段形状の雄ねじ山の転造時における肌荒れや雄ねじ山山頂部の割れの生成を有効に防止できる。   Furthermore, according to the present invention, it is possible to effectively prevent rough skin and generation of cracks at the top of the male screw thread when rolling a conventional two-stage male screw thread.

本発明に係るセルフタッピングねじを示す側面図である。It is a side view which shows the self-tapping screw which concerns on this invention. 同ねじ軸の拡大断面図である。It is an expanded sectional view of the screw shaft. 同微小円弧面の拡大断面図である。It is an expanded sectional view of the same microarc surface. （Ａ）・（Ｂ）・（Ｃ）・（Ｄ）は、本発明に係るセルフタッピングねじのねじ込む状態を段階を追って示す説明図である。(A) * (B) * (C) * (D) is explanatory drawing which shows the state in which the self-tapping screw which concerns on this invention is screwed in step by step. 本発明に係るセルフタッピングねじの初期ねじ込みトルク及び破壊トルクを示すグラフである。It is a graph which shows the initial screwing torque and breaking torque of the self-tapping screw which concerns on this invention. 比較例のセルフタッピングねじの初期ねじ込みトルク及び破壊トルクを示すグラフである。It is a graph which shows the initial screwing torque and breaking torque of the self-tapping screw of a comparative example.

本発明は、ねじ頭から垂下するねじ軸を有し、ねじ頭直下に延びるねじ軸部分にねじ山の高さが互いに等高の複数の等高雄ねじ山を形成し、同ねじ軸の先端軸部にねじ山の高さが該先端軸部端面に向かって漸減する複数の低背雄ねじ山を上記等高雄ねじ山と連続して形成し、該低背雄ねじ山の上下フランク面と上下谷底面との各連設部に微小円弧面をそれぞれ連続して形成すると共に、該微小円弧面を上記低背雄ねじ山に連続する端部等高雄ねじ山の少なくとも下フランク面と下谷底面との連設部に亘って延在するように形成したことにより、小さいねじ込みトルクで、精度の高い雌ねじを刻設して、大きな締結力を得ることができる。   The present invention has a screw shaft that hangs down from a screw head, and a plurality of contour male threads having the same thread height are formed on a screw shaft portion that extends directly below the screw head, and the tip shaft of the screw shaft A plurality of low-profile male threads that continuously decrease in height toward the end face of the tip shaft section, and the upper and lower flanks and upper and lower valley bottom surfaces of the lower-profile male threads, And continuously forming at least the lower flank surface and the bottom of the bottom valley of the high male thread that is continuous with the low-profile male thread. By forming so as to extend over the portion, it is possible to engrave a high-precision female screw with a small screwing torque and obtain a large fastening force.

以下、本発明を図示する好適な実施例に基づいて詳述すれば、該実施例に係るセルフタッピングねじは、図１に示す如く、基本的には、従来のセルフタッピングねじと同様に、
ねじ頭１と、該ねじ頭１下面中央から垂下する円柱軸から成るねじ軸２とを有する構成となっているが、特徴とするところは、図２にも示す如く、上記ねじ軸２は全長において等径の軸であり、ねじ頭１直下に延びるねじ軸２部分にねじ山の高さが互いに等高の複数の等高雄ねじ山３を形成し、同ねじ軸２の先端軸部にねじ山の高さが該先端軸部端面に向かって漸減する複数の低背雄ねじ山４を上記等高雄ねじ山３と連続して形成し、該低背雄ねじ山４の上下フランク面５と上下谷底面６との各連設部に微小円弧面７をそれぞれ連続して形成すると共に、該微小円弧面７を上記低背雄ねじ山４に連続する端部等高雄ねじ山３ａの少なくとも下フランク面５と下谷底面６との連設部に亘って延在するように形成した点にある。 Hereinafter, the self-tapping screw according to the present embodiment will be described in detail based on a preferred embodiment shown in the drawings. The self-tapping screw according to the embodiment is basically similar to the conventional self-tapping screw as shown in FIG.
The screw head 1 and the screw shaft 2 formed of a cylindrical shaft that hangs down from the center of the lower surface of the screw head 1 are characterized in that, as shown in FIG. Are formed in a portion of the screw shaft 2 extending directly below the screw head 1, and a plurality of contour male threads 3 having the same thread height are formed on the tip shaft portion of the screw shaft 2. A plurality of low-profile male screw threads 4 whose ridge height gradually decreases toward the end face of the tip shaft portion are formed continuously with the iso-high male screw threads 3, and the upper and lower flank surfaces 5 and upper and lower valley bottoms of the low-profile male screw threads 4 are formed. A micro arc surface 7 is continuously formed in each continuous portion with the surface 6, and the micro arc surface 7 is at least a lower flank surface 5 of an end equal height male screw thread 3 a continuous with the low profile male screw thread 4. And the bottom valley bottom surface 6 are formed so as to extend over a continuous portion.

尚、本実施例に係るセルフタッピングねじにおいては、低背雄ねじ山４の高さが漸減する角度αは、６度から１２度の範囲で設定する。また、フランク面５は、断面視直線面から成り、谷底面６は、ねじ軸２の軸線と平行な面であり、各雄ねじ山３・４は、この平行谷底面６を介し所定のピッチで配置されている。 In the self-tapping screw according to the present embodiment, the angle α at which the height of the low profile male thread 4 gradually decreases is set in the range of 6 degrees to 12 degrees. Further, the flank surface 5 is formed of a straight surface in cross section, and the valley bottom surface 6 is a surface parallel to the axis of the screw shaft 2. The male thread threads 3 and 4 are arranged at a predetermined pitch via the parallel valley bottom surface 6. Has been placed.

上記各雄ねじ山３・４の稜線は、尖鋭な稜線にするか図示のように僅かな平面１１（アール面を含む）を持った稜線にする。
また、実施例においては、端部等高雄ねじ山３ａの上フランク面５と上谷底面６との連設部には上記微小円弧面７を形成していない。同様に他の等高雄ねじ山３の上下フランク面５と上下谷底面６との各連設部にも上記微小円弧面を形成していない。即ち、何れの場合も直線面から成るフランク面５と同谷底面６とが鈍角に交わる。この場合、同所に加工上回避しがたい上記微小円弧面７よりも小さな円弧面を存して連設される場合を排除しない。 The ridgeline of each of the male screw threads 3 and 4 is a sharp ridgeline or a ridgeline having a slight plane 11 (including a rounded surface) as shown in the figure.
Further, in the embodiment, the minute arc surface 7 is not formed at the connecting portion between the upper flank surface 5 and the upper valley bottom surface 6 of the end-like high male thread 3a. Similarly, the minute arc surface is not formed in each connecting portion of the upper and lower flank surfaces 5 and the upper and lower valley bottom surfaces 6 of the other contour male thread 3. That is, in any case, the flank surface 5 made of a straight surface and the valley bottom surface 6 intersect at an obtuse angle. In this case, the case where a circular arc surface smaller than the above-mentioned micro circular arc surface 7 which is difficult to avoid in machining is not excluded at the same place.

好ましくは、図３に示す如く、上記低背雄ねじ山４及び端部等高雄ねじ山３ａの微小円弧面７の曲率半径Ｒをねじ軸の軸径に応じ０．２ミリメートルから０．６ミリメートルに設定する。また、図２に示す如く、上記構成を採りながら、等高雄ねじ山３の断面形状を左右対称形状にし且つその山角度βを４８度から５２度の範囲に設定する。   Preferably, as shown in FIG. 3, the curvature radius R of the small circular arc surface 7 of the low-profile male thread 4 and the high-end male thread 3a is changed from 0.2 millimeters to 0.6 millimeters according to the shaft diameter of the screw shaft. Set. In addition, as shown in FIG. 2, while adopting the above-described configuration, the cross-sectional shape of the contour male thread 3 is made symmetrical, and the mountain angle β is set in the range of 48 to 52 degrees.

本発明によれば、従来の二段形状の雄ねじ山の転造時における肌荒れや雄ねじ山山頂の割れの生成を有効に防止できる。   ADVANTAGE OF THE INVENTION According to this invention, the production | generation of the rough skin at the time of rolling of the conventional two-stage male screw thread and the crack of a male screw thread peak can be prevented effectively.

実際の使用に際しては、まず、相手部材８の下穴８ａ（ねじ軸２と等径の真円孔）と取付部材１０の取付孔１０ａとを一致させながら、相手部材８と取付部材１０を重ねた後、取付部材１０の取付孔１０ａ側から相手部材８の下穴８ａ内にねじ軸２の先端軸部をねじ込んでいくこととなるが、この際には、図４（Ａ）乃至（Ｂ）に示す如く、高さが漸減する低背雄ねじ山４の形成と、該低背雄ねじ山４及び端部等高雄ねじ山３ａに形成した微小円弧面７との相乗により、ねじ込み初期における相手部材８へのストレスが緩和され、スムーズに雌ねじ溝９を形成でき、初期ねじ込みトルクの軽減に寄与することができる。   In actual use, first, the mating member 8 and the mounting member 10 are overlapped while the pilot hole 8a (a round hole having the same diameter as the screw shaft 2) and the mounting hole 10a of the mounting member 10 are aligned. After that, the tip shaft portion of the screw shaft 2 is screwed into the lower hole 8a of the mating member 8 from the mounting hole 10a side of the mounting member 10, and in this case, FIGS. ), The mating member in the initial stage of screwing is formed by synergy between the formation of the low-profile male screw thread 4 that gradually decreases in height and the micro-arc surface 7 formed on the low-profile male screw thread 4 and the high-end male screw thread 3a. 8 is relieved, the female thread groove 9 can be formed smoothly, and it can contribute to the reduction of the initial screwing torque.

そして、更にねじ軸２をねじ込んでいくと、今度は、微小円弧面７が形成された低背雄ねじ山４により形成された雌ねじ溝９に端部等高雄ねじ山３側から等高雄ねじ山３が入り込むこととなるが、この際には、図４（Ｃ）乃至（Ｄ）に示す如く、微小円弧面７が形成された低背雄ねじ山４で成形された微小凸曲面部９ａにより、後続する等高雄ねじ山３のフランク面５と谷底面６との角隅部への材料移動がスムーズになされ、精度の高い雌ねじ溝９を形成することができる。依って、等高雄ねじ山３と雌ねじ溝９との確実な係合が得られ、大きな締結力を得ることができる。また、微小円弧面７が端部等高雄ねじ山３ａに亘って形成されることにより、低背雄ねじ山４から等高雄ねじ山３への移行が極めてスムーズに行え、移行部における相手部材に加わるストレスを軽減できる。   Then, when the screw shaft 2 is further screwed in, the equal height male thread 3 from the end equal height male thread 3 side into the female thread groove 9 formed by the low profile male thread 4 formed with the minute arcuate surface 7 is now obtained. In this case, as shown in FIGS. 4 (C) to (D), the succeeding portion is formed by the minute convex curved surface portion 9a formed by the low profile male screw thread 4 formed with the minute arcuate surface 7. The material movement to the corners of the flank surface 5 and the valley bottom surface 6 of the contoured male screw thread 3 is made smoothly, and a highly accurate female screw groove 9 can be formed. Therefore, reliable engagement between the contour male thread 3 and the female thread groove 9 is obtained, and a large fastening force can be obtained. In addition, since the minute circular arc surface 7 is formed over the end portion of the high male thread 3a, the transition from the low-profile male screw thread 4 to the constant height male screw thread 3 can be performed very smoothly, and is added to the mating member at the transition portion. Can reduce stress.

また、破壊トルクを大きく、初期ねじ込みトルクを小さくすることができるので、ねじ込みトルク間隔を広く取ることができるため、合成樹脂や金属からなる相手部材に対する共通トルク帯域を確保でき、何れの材料に対しても、安定してねじ込み作業を行うことができる。   In addition, since the breaking torque can be increased and the initial screwing torque can be reduced, the screwing torque interval can be widened, so that a common torque band can be secured for the mating member made of synthetic resin or metal, and any material can be secured. However, the screwing operation can be performed stably.

ここで、本実施例に係るセルフタッピングねじの有効性について、確認試験の結果を踏まえて説明する。   Here, the effectiveness of the self-tapping screw according to the present embodiment will be described based on the result of the confirmation test.

素材の異なる４種類の相手部材（金属鋼板・ＡＢＳ樹脂材・ポリカーボネートとＡＢＳ樹脂との重合材又はポリカーボネートとＡＳ樹脂の重合材）について、図５は、本発明に係るセルフタッピングねじの初期ねじ込みトルク及び破壊トルクを測定したものであり、図６は、本発明に係る低背雄ねじ山４と微小円弧面７とを形成しない比較例に係るセルフタッピングねじの初期ねじ込みトルク及び破壊トルクを測定したものである。   FIG. 5 shows the initial screwing torque of the self-tapping screw according to the present invention for four types of mating members of different materials (metal steel plate, ABS resin material, polymer material of polycarbonate and ABS resin, or polymer material of polycarbonate and AS resin). FIG. 6 shows the measurement of the initial screwing torque and the breaking torque of the self-tapping screw according to the comparative example in which the low-profile male screw thread 4 and the minute circular arc surface 7 according to the present invention are not formed. It is.

図５・図６から明らかな如く、全種類の相手部材において、本発明に係るセルフタッピングねじの初期ねじ込みトルクの方が、比較例のセルフタッピングねじの初期ねじ込みトルクよりも小さいことが確認できると共に、全種類の相手部材において、本発明に係るセルフタッピングねじの破壊トルクの方が、比較例のセルフタッピングねじの破壊トルクよりも大きいことが確認できる。   As apparent from FIGS. 5 and 6, it can be confirmed that the initial screwing torque of the self-tapping screw according to the present invention is smaller than the initial screwing torque of the self-tapping screw of the comparative example in all types of mating members. In all types of mating members, it can be confirmed that the breaking torque of the self-tapping screw according to the present invention is larger than the breaking torque of the self-tapping screw of the comparative example.

また、図５から明らかな如く、本発明に係るセルフタッピングねじにおいては、上述のように、破壊トルクを大きく、初期ねじ込みトルクを小さくすることができるので、ねじ込みトルク間隔を広く取ることができるため、合成樹脂や金属からなる相手部材に対する共通トルク帯域Ｓ１を充分に確保でき、何れの材料に対しても、安定してねじ込み作業を行うことができる。   Further, as apparent from FIG. 5, in the self-tapping screw according to the present invention, as described above, the breaking torque can be increased and the initial screwing torque can be reduced, so that the screwing torque interval can be widened. The common torque band S1 for the mating member made of synthetic resin or metal can be sufficiently secured, and the screwing operation can be stably performed for any material.

また、図６から明らかな如く、比較例のセルフタッピングねじにおいては、上述のように、破壊トルクと初期ねじ込みトルクの間隔が狭いため、合成樹脂や金属からなる相手部材に対する共通トルク帯域Ｓ２を充分に確保できず、材質毎に専用のねじを使用せねばならない。   Further, as is clear from FIG. 6, in the self-tapping screw of the comparative example, as described above, since the interval between the breaking torque and the initial screwing torque is narrow, the common torque band S2 for the mating member made of synthetic resin or metal is sufficient. It is necessary to use a dedicated screw for each material.

本発明に係るセルフタッピングねじは、小さいねじ込みトルクで、精度の高い雌ねじを刻設して、大きな締結力を得ることができるので、これを電子機器、通信機器、事務機器等において、合成樹脂や金属からなる相手部材に部品等の取付部材を取り付けるために利用すれば、頗る好都合なものとなる。   Since the self-tapping screw according to the present invention can obtain a large fastening force by engraving a high-precision female screw with a small screwing torque, this can be used in electronic equipment, communication equipment, office equipment, etc. If it is used to attach a mounting member such as a part to a mating member made of metal, it will be very convenient.

１ ねじ頭
２ ねじ軸
３ 等高雄ねじ山
３ａ 端部等高雄ねじ山
４ 低背雄ねじ山
５ フランク面
６ 谷底面
７ 微小円弧面
８ 相手部材
８ａ 下穴
９ 雌ねじ溝
９ａ 微小円弧面で成形される微小凸曲面部
１０ 取付部材
１０ａ 取付孔
１１ 平面から成る稜線
α 低背雄ねじ山の高さが漸減する角度
β 等高雄ねじ山の山角度
Ｒ 微小円弧面の曲率半径 DESCRIPTION OF SYMBOLS 1 Screw head 2 Screw shaft 3 Equal height male thread 3a End equal height male screw thread 4 Low profile male screw thread 5 Frank surface 6 Valley bottom surface 7 Micro arc surface 8 Mating member 8a Pilot hole 9 Female thread groove 9a It shape | molds by micro arc surface Micro-convex curved surface portion 10 Mounting member 10a Mounting hole 11 Plane ridge line α Angle at which the height of the low-profile male screw thread gradually decreases β Angle angle of the iso-high male screw thread R The radius of curvature of the micro-arc surface

Claims (4)

ねじ頭から垂下するねじ軸を有し、ねじ頭直下に延びるねじ軸部分にねじ山の高さが互いに等高の複数の等高雄ねじ山を形成し、同ねじ軸の先端軸部にねじ山の高さが該先端軸部端面に向かって漸減する複数の低背雄ねじ山を上記等高雄ねじ山と連続して形成し、該低背雄ねじ山の上下フランク面と上下谷底面との各連設部に微小円弧面をそれぞれ連続して形成すると共に、該微小円弧面を上記低背雄ねじ山に連続する端部等高雄ねじ山の少なくとも下フランク面と下谷底面との連設部に亘って延在するように形成したことを特徴とするセルフタッピングねじ。   The screw shaft has a screw shaft that hangs down from the screw head. A plurality of contour male threads with the same height are formed on the screw shaft portion that extends directly below the screw head, and the screw thread is formed on the tip shaft portion of the screw shaft. A plurality of low-profile male threads that are gradually decreased toward the end face of the tip shaft portion, and are formed continuously with the contour male threads, and the lower and upper flank surfaces and upper and lower valley bottom surfaces of the low-profile male threads are connected to each other. A small arc surface is continuously formed on the portion, and the micro arc surface is extended over at least the lower flank surface and the bottom valley bottom surface of the high-end male thread that is continuous with the low-profile male thread. A self-tapping screw characterized by being formed to extend. 上記低背雄ねじ山及び端部等高雄ねじ山に形成した微小円弧面が０．２ミリメートルから０．６ミリメートルの曲率半径を有することを特徴とする請求項１記載のセルフタッピングねじ。   2. The self-tapping screw according to claim 1, wherein the small circular arc surface formed on the low-profile male thread and the high-end male thread has a curvature radius of 0.2 mm to 0.6 mm. 上記低背雄ねじ山と連続する等高雄ねじ山の断面形状が左右対称形状を有し、４８度から５２度の山角度を有することを特徴とする請求項１乃至請求項２のいずれかに記載のセルフタッピングねじ。   The cross-sectional shape of a contour male thread continuous with the low-profile male thread has a left-right symmetric shape, and has a thread angle of 48 to 52 degrees. Self tapping screw. 上記ねじ軸が全長において等径の円柱軸であり、該等径の先端軸部に上記低背雄ねじ山が形成されていることを特徴とする請求項１乃至請求項３のいずれかに記載のセルフタッピングねじ。   4. The screw shaft according to claim 1, wherein the screw shaft is a cylindrical shaft having an equal diameter in the entire length, and the low-profile male screw thread is formed on the tip shaft portion having the same diameter. Self tapping screw.
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US8371787B2 (en) 2013-02-12

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